This invention relates to a method and apparatus for determining whether conditions are proper for deploying a safety restraint device in a vehicle occupant restraining system.
Vehicle occupant restraining systems utilize various different safety restraint devices, such as airbags, to prevent passengers from experiencing severe injuries in the event of a vehicle crash. The airbags can be located at different locations within the vehicle, such as in the steering wheel, dashboard, or door panels, for example.
In response to a vehicle crash, a central controller determines which of the safety restraint devices should be deployed and also determines whether the crash conditions are sufficient to warrant deployment. To make this decision, the central controller analyzes data from many different vehicle sensors. These sensors can include accelerometers, roll angular rate sensors, and crash sensors, for example.
One disadvantage with this system is that if the central controller is experiencing problems, improper deployment decisions could be made. For example, the central controller could decide to deploy an airbag in a situation where a deployment is undesirable or could fail to issue a deployment command when an airbag should be deployed. The central controller may not be operating properly for various different reasons. There could be problems with the sensors, which could result in a fault or non-receipt of data error. In this situation, the central controller may not have sufficient data to make a decision. Or, there could be a problem with the central controller itself, in which case the central controller may not be able to process the steps in an efficient and accurate manner to generate the proper control signal.
Thus, it is desirable to have a method and apparatus that can verify whether or not deployment of the safety restraint device is proper, as well as overcoming the other above mentioned deficiencies with the prior art.
A vehicle occupant restraining system includes a plurality of safety restraint devices and utilizes a main controller and a safing controller to determine which safety restraint devices should be deployed, and further determines whether or not conditions are proper for deployment. The system discriminates between front, side, rear, and roll-over impact events and independently determines whether to activate a fuel cut-off switch in response to an impact event. The main and safing controllers utilize vehicle data from a main center tunnel sensor assembly and various satellite sensors to make deployment decisions. The safing controller is used to independently verify whether or not the safety restraint should be deployed.
In one disclosed embodiment, the main center tunnel sensor assembly includes a longitudinal sensor for generating a longitudinal sensor signal, a lateral sensor for generating a lateral sensor signal, and a vertical sensor for generating a vertical sensor signal. The satellite sensor assembly includes at least one front impact sensor for generating a front impact sensor signal and a plurality of side impact sensors, positioned at various different locations on the sides of the vehicle, for generating a plurality of side impact sensor signals. The satellite sensor assembly also preferably includes at least one rear impact sensor for generating a rear impact sensor signal.
In a front impact event, the main controller determines whether to deploy a front impact related safety restraint device via primary and secondary safing actuators. The main controller generates an arming threshold based on the longitudinal sensor signal or the front impact sensor signal and subsequently generates a safety restraint device deployment request based on the longitudinal sensor signal and the front impact sensor signal. The safing controller generates a deployment decision for front impact related safety restraint devices based on the longitudinal sensor signal. The safing controller does this independently of the arming threshold and safety restraint device deployment request as generated by the main controller. The primary and secondary safing actuators are enabled only after the deployment decision for front impact related safety restraint devices and the arming threshold have been generated. The front impact related safety restraint devices are deployed in response to the primary and secondary safing actuators being enabled in combination with the safety restraint device deployment request being generated. Preferably, the primary safing actuator comprises a transistor switch and the secondary safing actuator comprises a deployment enable signal that enables activation components necessary for the deployment of the associated safety restraint devices, with the exception of the primary safing actuator.
In a side impact event, the main controller determines whether to deploy a side impact related safety restraint device via primary and secondary safing actuators. The main controller generates an arming threshold based on at least one of the side impact sensor signals and subsequently generates a safety restraint device deployment request based on either the longitudinal sensor signal and at least one of the side impact sensor signals, the lateral sensor signal and at least one of the side impact sensor signals, or at least two side impact sensor signals. The safing controller generates a deployment decision for side impact related safety restraint devices based on at least one of the side impact sensor signals. The safing controller does this independently of the arming threshold and safety restraint device deployment request as generated by the main controller. The primary and secondary safing actuators are enabled only after the deployment decision for side impact related safety restraint devices and the arming threshold have been generated. The side impact related safety restraint devices are deployed in response to the primary and secondary safing actuators being enabled in combination with the safety restraint device deployment request being generated. The primary and secondary safing actuators operate similarly to that described above.
In a rear impact event, the main controller determines whether to deploy a rear impact related safety restraint device via primary and secondary safing actuators. The main controller generates an arming threshold based on the longitudinal sensor signal or the rear impact sensor signal and subsequently generates a safety restraint device deployment request based on the longitudinal sensor signal and the rear impact sensor signal. The safing controller generates a deployment decision for rear impact related safety restraint devices based on the longitudinal sensor signal. The safing controller does this independently of the arming threshold and safety restraint device deployment request as generated by the main controller. The primary and secondary safing actuators are enabled only after the deployment decision for rear impact related safety restraint devices and the arming threshold have been generated. The rear impact related safety restraint devices are deployed in response to the primary and secondary safing actuators being enabled in combination with the safety restraint device deployment request being generated. Preferably, the primary and secondary safing actuators operate as described above.
In one disclosed embodiment, the main sensor assembly includes a roll angular rate sensor for generating a roll angular rate signal. In a roll-over impact event, the main controller determines whether to deploy a roll-over impact related safety restraint device with primary and secondary safing actuators. The main controller generates an arming threshold based on the roll angular rate sensor signal or the lateral sensor signal and subsequently generates a safety restraint device deployment request based on the roll angular rate sensor signal and the lateral sensor signal or the vertical sensor signal. The safing controller generates a deployment decision for roll-over impact related safety restraint devices based on the roll angular rate sensor signal. The safing controller does this independently of the arming threshold and safety restraint device deployment request as generated by the main controller. The primary and secondary safing actuators are enabled only after the deployment decision for roll-over impact related safety restraint devices and the arming threshold have been generated. The roll-over impact related safety restraint device is deployed in response to the primary and secondary safing actuators being enabled in combination with the safety restraint device deployment request being generated. The primary and secondary safing actuators operate similarly to that described above.
In one disclosed embodiment, the main controller determines whether to generate a fuel-cut-off signal in response to an impact event. The main controller determines whether to generate the fuel cut-off signal independently from the safety restraint device deployment decisions. The main controller compares the lateral and longitudinal sensor signals to a predetermined threshold and generates the fuel cut-off signal if a sum of the lateral and longitudinal sensor signals exceeds a first static threshold. The main controller discriminates between roll-over, front, side, and rear impact events before generating the fuel cut-off signal and compares the sum of the lateral and longitudinal sensor signals to a second static threshold, lower than the first static threshold. If the second static threshold is exceeded, the main controller determines a velocity direction of the longitudinal sensor signal and activates a fuel cut-off switch if the velocity direction indicates a rear impact event.
The subject system and method provides a more accurate and efficient method for determining whether or not conditions are proper for safety restraint deployment by utilizing independent deployment verification. These and other features of the present invention can be best understood from the following specifications and drawings, the following of which is a brief description.